“My ex has ruined my relationship” Please Help

I got in touch with my ex after my man and I had a misunderstanding and didn’t talk for almost a week. My ex and I dated for almost three years, he knews me better, and he understands me as well. My current man and I have however, dated for just a nine months so I often get in touch with my ex when things aren’t going well between us. He helps me to calm down and sometimes, advices me.

So when my man and I had the issue, I called my ex and we linked up as usual. We made out (had s£×) mistakenly but it happened twice within that same week.
Later on, my ex called my current guy to tell him he was still f*c|<¡ng me so he should dump me and find a more faithful woman who doesn’t go back to her ex.
He stole the guy’s number from my phone and called him to tell him that. He even sent him chats that I had with him while I was complaining and telling him (my ex) about some things I didn’t like about my current guy.

Bro Kay, is it fair? I gave him a chance to sl££p with me again so he thought I still loved him and even have the guts to tell my man to dump me cuz I’m cheap.
I’ve tried to beg my man but he won’t listen Kwaku. My ex has ruined my relationship. Is it a crime that I gave him a chance to enter me? He told me he did it for the guy and not me. Why are soo wicked? All the times I made out with him after the break up, he was always the one that initiated it. Yes, I visited but I don’t initiate s£x, he does always.
Please what can I do to earn my man’s trust and make him pardon me? I can’t lose this guy too, he’s good to me. Please advise me.